Slide rail assembly

ABSTRACT

A slide rail assembly includes a first rail, a second rail and a positioning device. The first rail includes a first structure and a second structure. The second rail is movable relative to the first rail. The positioning device is arranged to the second rail and includes an elastic member and a positioning member. The elastic member provides an elastic force to the positioning member. When the second rail is moved relative to the first rail from a first position to a second position, the positioning member is moved to an engaging position through the elastic force and abuts against the first structure. When the second rail is moved relative to the first rail from the second position to a third position, the positioning member is moved from the engaging position to a disengaging position and no longer abuts against the first structure by guidance of the second structure.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser. No. 16/205,229, filed on Nov. 30, 2018. This application claims the benefit of U.S. application Ser. No. 16/205,229, which was filed on Nov. 30, 2018, and is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a slide rail assembly, and more particularly, to a slide rail assembly comprising at least two slide rails.

2. Description of the Prior Art

A slide rail assembly is widely used. For example, it can be used to mount a drawer movable relative to a cabinet, or to mount a chassis of an electric apparatus movable relative to a rack (or a cabinet). Wherein, the slide rail assembly commonly has three slide rails and composes a so-called three-slide-rail assembly.

For example, the three-slide-rail assembly comprises a first rail, a second rail and a third rail movably connected to each other. Wherein, the second rail can be located at an extending position relative to the first rail, and when the second rail is located at the extending position, the second rail and the first rail usually have engaging means collocating with each other to prevent the second rail from being opened or retracted arbitrarily relative to the first rail in a direction. Conventional methods to sever the engagement usually take advantage of displacement of the third rail to sever an engaging relationship of the engaging means. Otherwise, users operate related components of the engaging means in a manual manner directly to sever the engaging relationship of the engaging means.

U.S. Pat. No. 6,997,611 B2 of Chen et al. discloses a positioning device 6 disposed to an intermediate slide track 2. When an inner slide track 1 and the intermediate slide track 2 are pulled relative to an outer slide track 3 to an extending position, the intermediate slide track 2 is held in an extending positioning state relative to the outer slide track 3. For retraction operation, the prior art discloses that the positioning state is severed through the inner slide track retracted relative to the intermediate slide track such that the inner slide track and the intermediate slide track are retractable relative to the outer slide track. However, when the inner slide track is detached from the intermediate slide track, the intermediate slide track is still in the extending state relative to the outer slide track. If the users want to retract the intermediate slide track relative to the outer slide track, they have to stretch their hands to the rear of the intermediate slide track to directly operate the positioning device and sever the positioning relationship between the intermediate slide track and the outer slide track to enable the intermediate slide track to be retracted relative to the outer slide track. Obviously, the operation is not very convenient. Especially when slide tracks have been mounted to a rack, the operation which needs the users to stretch their hands into the rack to sever the positioning relationship between the intermediate slide track and the outer slide track lacks convenience for personnel.

In US patent application number 2011/0135224 of Chen et al., a slide assembly is disclosed to be including a first slide member 12 having a guiding base 36 and a lock portion 40, a second slide member 14 having a first slide segment 16 and a second slide segment 18, a third slide member 22 movably mounted on the second slide segment 18, an aid-sliding member 20 slidably connected between the first slide member 12 and the first slide segment 16, and a positioning device 24 connected to the second slide member 14. The positioning device 24 includes an elastic member 78 and a positioning member 80 which is movable by a force of the elastic member 78, so that two ends of the positioning member 80 are respectively located corresponding to the guiding base 36 and the third slide member 22. The positioning member 80 is engaged with the lock portion 40 when the second slide member 14 is moved (extended) relative to the first slide member 12, and is disengaged from the lock portion 40 when the third slide member 22 is retracted relative to the second slide member 14. However, to disengage the positioning device 24 and positioning member 80 from the lock portion 40, the third slide member 22 is moved (retracted) relative to the second slide member 14 such that the protrusion 76 of the third slide member 22 abuts an end of the positioning member 80 for the positioning member 80 to be rotated and disengaged from the lock portion 40; the lock portion 40 remains stationary and do not participate in the disengaging mechanism.

In US patent application number 2011/0280506 of Chen et al., a positioning device 50 of a slide assembly includes a first rail 10, a second rail 20 slidably connected to the first rail 10 and defining a path 26, and a third rail 30 slidably connected to the path 26 of the second rail 20. A positioning member 52 is securely connected to the second rail 20. An engaging member 68 is pivotably connected to the positioning member 52 and includes an extension arm 72 located corresponding to the positioning portion 16 of the first rail 10 and capable of engaging with the positioning portion 16. An extension wing 76 has an inclined surface 19 relative to a horizontal plane and extending toward the path 26 of the second rail 20. A resilient member 84 is connected to the engaging member 68 and makes the extension wing 76 of the engaging member 68 slide toward the third rail 30. When the third rail 30 is retracted relative to the second rail 20, the engaging member 68 is disengaged from the positioning portion 16 of the first rail 10. In other words, the third rail 30 is moved in an extension direction relative to the second rail 20 to engage the engaging member 68 with the positioning portion 16, and the third rail 30 is moved in a retraction direction (opposite to the extension direction) relative to the second rail 20 to disengage the engaging member 68 from the positioning portion 16.

Therefore, the slide rail assemblies of the prior art require the rails to move in one direction to be engaged with each other, and move in an opposite direction to disengaged with each other. In view of the available prior art, how to develop a different slide rail product depending on various market demands has become a discussable issue.

SUMMARY OF THE INVENTION

The present invention relates to a slide rail assembly comprising at least two slide rails.

According to an embodiment of the present invention, a slide rail assembly comprises a first rail, a second rail and a positioning device. The first rail comprises a first structure and a second structure. The second rail is movable relative to the first rail. The positioning device is arranged to the second rail and comprises an elastic member and a positioning member. The positioning member is located at an initial position in response to an elastic force generated by the elastic member. When the second rail is moved relative to the first rail from a first position to a second position in a first direction, the positioning member is moved from the initial position to an engaging position through the elastic force released by the elastic member and abuts against the first structure of the first rail. When the second rail is moved relative to the first rail from the second position to a third position in the first direction, the positioning member is moved from the engaging position to a disengaging position by guidance of the second structure of the first rail and no longer abuts against the first structure of the first rail.

Preferably, the slide rail assembly further comprises a third rail movable relative to the second rail and a synchronizing member pivoted to the second rail. The third rail has a synchronizing feature. The second rail and the third rail are capable of being moved synchronously by means of abutting between the synchronizing feature and the synchronizing member.

Preferably, the first rail further comprises a first severing feature. When the second rail is located at the second position relative to the first rail, the first severing feature of the first rail is configured to sever a synchronous relationship between the second rail and the third rail.

Preferably, the first severing feature comprises an incline or a cambered surface, and the synchronizing member is deflectable through contacting the first severing feature to serve the synchronous relationship between the second rail and the third rail.

Preferably, the first structure is a hole or a concaved portion. The second structure is adjacent to the first structure, and the second structure comprises an incline or a cambered surface.

Preferably, the first position is a retracted position, the second position is a first extending position, and the third position is a second extending position.

Preferably, the slide rail assembly further comprises a holding member arranged to the second rail. The positioning member is pivoted to the second rail. When the positioning member is located at the disengaging position, the positioning member can be held at the disengaging position by the holding member.

Preferably, the holding member has a flexible portion. The flexible portion is able to exert a holding force to the positioning member.

Preferably, the first rail further comprises a second severing feature. When the second rail is moved relative to the first rail to the first position in a second direction, the positioning member is released from the holding force and moved from the disengaging position back to the initial position by guidance of the second severing feature of the first rail.

Preferably, the second severing feature of the first rail is an incline or a cambered surface.

Preferably, the slide rail assembly further comprises an operating member arranged to the first rail. The operating member comprises a first blocking portion. The second rail has a second blocking portion. When the second rail is moved relative to the first rail to the second position, the first blocking portion and the second blocking portion obstruct each other to prevent the second rail from being moved in the first direction.

Preferably, the operating member is operable to drive the first blocking portion to leave the blocking position and no longer obstruct the second blocking portion of the second rail such that the second rail is movable relative to the first rail to the third position in the first direction.

Preferably, the slide rail assembly further comprises an auxiliary sliding device arranged between the first rail and the second rail. The auxiliary sliding device comprises a pair of bead strips. Each bead strip comprises a plurality of balls configured to support the first rail and the second rail.

Preferably, the second rail has a rear blocking portion corresponding to a rear end of the each bead strip. The first rail has a front blocking portion corresponding to a front end of the each bead strip. The each bead strip is located between the front blocking portion of the first rail and the rear blocking portion of the second rail. When the second rail is located at the second position relative to the first rail, a clearance is between the front end of the each bead strip and the front blocking portion of the first rail.

These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a slide rail assembly according to an embodiment of the present invention mounted to a rack.

FIG. 2 is a diagram showing a composition of the slide rail assembly according to the embodiment of the present invention.

FIG. 3 is a diagram showing a decomposition of the slide rail assembly according to the embodiment of the present invention.

FIG. 4 is a diagram showing a decomposition of a positioning device, a synchronizing member, a holding member and a second rail of the slide rail assembly according to the embodiment of the present invention.

FIG. 5 is a diagram showing a composition of the positioning device, the synchronizing member, the holding member and the second rail of the slide rail assembly according to the embodiment of the present invention.

FIG. 6 is a diagram showing the second rail and a third rail retracted relative to a first rail of the slide rail assembly according to the embodiment of the present invention.

FIG. 7 is a partial enlarged diagram showing zone A in FIG. 6.

FIG. 8 is a diagram showing the second rail and the third rail moved synchronously relative to the first rail to a position in a first direction according to the embodiment of the present invention.

FIG. 9 is a partial enlarged diagram showing zone A in FIG. 8.

FIG. 10 is a perspective diagram showing the second rail located at the position and a portion of an operating member of the first rail engaging the second rail according to the embodiment of the present invention.

FIG. 11 is a perspective diagram showing the second rail located at the position and the operating member of the first rail operated such that the portion no longer engages the second rail according to the embodiment of the present invention.

FIG. 12 is a diagram showing the second rail moved relative to the first rail from the position to another position in the first direction according to the embodiment of the present invention.

FIG. 13 is a partial enlarged diagram showing zone A in FIG. 12.

FIG. 14 is a diagram showing the second rail retracted relative to the first rail in a second direction according to the embodiment of the present invention.

FIG. 15 is a partial enlarged diagram showing zone A in FIG. 14.

FIG. 16 is a diagram showing the second rail further retracted relative to the first rail in the second direction according to the embodiment of the present invention.

FIG. 17 is a partial enlarged diagram showing zone A in FIG. 16.

DETAILED DESCRIPTION

As shown in FIG. 1, a slide rail assembly 20 according to an embodiment of the present invention can be mounted to a rack. Specifically, the slide rail assembly 20 can be mounted to a first post 26 a and a second post 26 b of the rack through a first bracket 22 and a second bracket 24.

As shown in FIG. 2 and FIG. 3, the slide rail assembly 20 comprises a first rail 28, a second rail 30 and a positioning device 32. Preferably, the slide rail assembly 20 further comprises a third rail 34, an operating member 36 and a synchronizing member 38.

The first rail 28 comprises a first structure 40 and a second structure 42. Preferably, the first rail 28 has a first wall 44 a, a second wall 44 b and a side wall 46 connected between the first wall 44 a and the second wall 44 b. The first wall 44 a, the second wall 44 b and the side wall 46 of the first rail 28 cooperatively define a passage 48. Preferably, the first rail 28 further comprises a first severing feature 50 and a second severing feature 52.

Preferably, the first structure 40, the second structure 42, the first severing feature 50 and the second severing feature 52 are arranged to the side wall 46 and in the passage 48. Preferably, the first structure 40 and the second structure 42 are located between a front portion 28 a and a rear portion 28 b of the first rail 28. Preferably, the first structure 40 is adjacent to the second structure 42. Preferably, the first structure 40 is a hole or a concaved portion, and the second structure 42 comprises an incline or a cambered surface. Preferably, the first severing feature 50 is parallel to the first structure 40 (the second structure 42). Preferably, the first severing feature 50 comprises an incline or a cambered surface. Preferably, the second severing feature 52 is arranged adjacently to the rear portion 28 b of the first rail 28. Preferably, the second severing feature 52 comprises an incline or a cambered surface.

It is notable that the second bracket 24 is adjustably arranged adjacently to the rear portion 28 b of the first rail 28. On the other hand, the first bracket 22 is attached adjacently to the front portion 28 a of the first rail 28. For example, the first bracket 22 is fixed adjacently to the front portion 28 a of the first rail 28 through riveting, welding and so on. Therefore, the first bracket 22 can be regarded as a part of the first rail 28. Preferably, the operating member 36 is arranged to the first bracket 22 of the first rail 28, and the operating member 36 comprises a first blocking portion 36 a. Preferably, the operating member 36 further comprises a resilient portion 36 b. The first blocking portion 36 a is arranged to the resilient portion 36 b, but is not limited thereto. Preferably, a position of the resilient portion 36 b is corresponding to a space 37 of the first rail 28. The space 37 communicates the passage 48 of the first rail 28.

The second rail 30 is movable longitudinally relative to the first rail 28. For example, the second rail 30 is movably mounted into the passage 48 of the first rail 28. Preferably, the second rail 30 has a first wall 58 a, a second wall 58 b and a side wall 60 connected between the first wall 58 a and the second wall 58 b. The first wall 58 a, the second wall 58 b and the side wall 60 of the second rail 30 cooperatively define a passage 62. Positions of the first wall 58 a, the second wall 58 b and the side wall 60 of the second rail 30 are corresponding to the first wall 44 a, the second wall 44 b and the side wall 46 of the first rail 28, respectively.

The positioning device 32 is arranged to the second rail 30. The positioning device 32 comprises a positioning member 64 and an elastic member 66 (this part can be referred to FIG. 4 and FIG. 5). Wherein, the elastic member 66 comprises a first elastic section 66 a configured to provide an elastic force to the positioning member 64. Preferably, the elastic member 66 further comprises a second elastic section 66 b configured to provide an elastic force to the synchronizing member 38. Preferably, the elastic member 66 is connected (e.g. fixed) to the side wall 60 of the second rail 30 through a connecting section 66 c. Preferably, the positioning member 64 and the synchronizing member 38 are pivoted to the second rail 30, and the positioning member 64 and the synchronizing member 38 are rotatable relative to each other. Hereby, the positioning member 64 and the synchronizing member 38 are pivoted to the side wall 60 of the second rail 30 via a shaft 68, and the positioning member 64 and the synchronizing member 38 rotate relative to each other as an example in the embodiment, but the present invention is not limited thereto. Preferably, the side wall 60 of the second rail 30 has a first hole H1, a second hole H2 and a third hole H3. Positions of the first hole H1 and the second hole H2 are corresponding to the positioning member 64 and the synchronizing member 38, respectively. The third hole H3 communicates with the first hole H1, and a position of the third hole H3 is corresponding to a third structure 64 b of the positioning member 64. Preferably, the positioning member 64 and the synchronizing member 38 are located adjacently to a rear portion 30 b of the second rail 30. Preferably, the slide rail assembly 20 further comprises a holding member 70 arranged to the second rail 30, and the holding member 70 has a flexible portion 70 a. The flexible portion 70 a is able to collaborate with an extending section 64 a of the positioning member 64, and the third structure 64 b of the positioning member 64 and the extending section 64 a are two ends of the positioning member 64, respectively. Preferably, the second rail 30 has a second blocking portion 74. The second blocking portion 74 is configured to collaborate with the first blocking portion 36 a of the operating member 36. Preferably, the second blocking portion 74 is a wall around a through hole 75 of the second rail 30. Preferably, the slide rail assembly 20 further comprises an auxiliary sliding device arranged between the first rail 28 and the second rail 30 to promote smoothness of motion of the second rail 30 relative to the first rail 28. Preferably, the auxiliary sliding device comprises a first bead strip 54 a and a second bead strip 54 b. Wherein, the first bead strip 54 a slidably abuts against the first wall 44 a of the first rail 28 and the first wall 58 a of the second rail 30 and is located therebetween; the second bead strip 54 b slidably abuts against the second wall 44 b of the first rail 28 and the second wall 58 b of the second rail 30 and is located therebetween. Each bead strip 54 a, 54 b has a predetermined longitudinal length and comprises a plurality of balls 55. Preferably, a front blocking portion 56 of the first rail 28 is disposed adjacently to the front portion 28 a of the first rail 28. Preferably, a pair of front blocking portions 56 is located on the first wall 44 a and the second wall 44 b of the first rail 28 as an example in the embodiment, and the pair of front blocking portions 56 is corresponding to front ends F of the first bead strip 54 a and the second bead strip 54 b. Preferably, a rear blocking portion 72 of the second rail 30 is disposed adjacently to a rear portion 30 a of the second rail 30. Preferably, a pair of rear blocking portions 72 is located on the first wall 58 a and the second wall 58 b of the second rail 30 as an example in the embodiment, and the pair of rear blocking portions 72 is corresponding to rear ends B of the first bead strip 54 a and the second bead strip 54 b.

The third rail 34 can be moved longitudinally relative to the second rail 30. For example, the third rail 34 is movably mounted into the passage 62 of the second rail 30. Preferably, the third rail 34 has a first wall 76 a, a second wall 76 b and a side wall 78 connected between the first wall 76 a and the second wall 76 b. Positions of the first wall 76 a, the second wall 76 b and the side wall 78 of the third rail 34 are corresponding to the first wall 58 a, the second wall 58 b and the side wall 60 of the second rail 30, respectively. Preferably, the third rail 34 has a synchronizing feature 80 configured to collaborate with the synchronizing member 38. Preferably, the synchronizing feature 80 is arranged to the side wall 78 of the third rail 34 as a protruded portion.

As shown in FIG. 3, FIG. 4, FIG. 6 and FIG. 7, the slide rail assembly 20 is in a retracted state. Specifically, the second rail 30 (and the third rail 34) is located at a first position P1 relative to the first rail 28 (e.g. a retracted position), but it is not limited thereto. Wherein, the positioning member 64 is able to be located at an initial position S1 in response to the elastic force generated by the first elastic section 66 a of the elastic member 66, and the third structure 64 b of the positioning member 64 is able to abut against the side wall 46 of the first rail 28 via the third hole H3 on the side wall 60 of the second rail 30. Wherein, when the positioning member 64 is located at the initial position 51, the extending section 64 a of the positioning member 64 is adjacent to the flexible portion 70 a of the holding member 70.

Preferably, when the second rail 30 is located at the first position P1 relative to the first rail 28, a portion of the second severing feature 52 of the first rail 28 can support the positioning member 64. Besides, a predetermined distance is between the positioning member 64 and the first structure 40 and the second structure 42 of the first rail 28. On the other hand, the synchronizing member 38 is able to be in an initial state X1 in response to the elastic force generated by the second elastic section 66 b of the elastic member 66. Wherein, when being in the initial state X1, the synchronizing feature 80 is able to abut against an engaging section 380 of the synchronizing member 38 so as to make the second rail 30 and the third rail 34 moved synchronously in a first direction D1. In addition, a predetermined distance is between the synchronizing member 38 and the first severing feature 50 of the first rail 28, and a predetermined distance is between the second blocking portion 74 of the second rail 30 and the first blocking portion 36 a of the operating member 36. Besides, the first bead strip 54 a and the second bead strip 54 b are located between the front blocking portion 56 of the first rail 28 and the rear blocking portion 72 of the second rail 30.

As shown in FIGS. 6-9, when the second rail 30 and the third rail 34 are moved synchronously relative to the first rail 28 from the first position P1 to a second position P2 (e.g. a first extending position) in the first direction D1, the positioning member 64 is moved from the initial position S1 (as shown in FIG. 6 or FIG. 7) to an engaging position S2 through the elastic force released by the first elastic section 66 a of the elastic member 66 so as to drive the third structure 64 b of the positioning member 64 to abuts against the first structure 40 of the first rail 28 (as shown in FIG. 8 or FIG. 9) to prevent the second rail 30 from being moved relative to the first rail 28 in a second direction D2 opposite to the first direction D1. Wherein, when the positioning member 64 is located at the engaging position S2, the extending section 64 a of the positioning member 64 slightly tilts up relative to the flexible portion 70 a of the holding member 70.

Preferably, when the second rail 30 is located at the second position P2 relative to the first rail 28, positions of the through hole 75 and the second blocking portion 74 of the second rail 30 are corresponding to the first blocking portion 36 a of the operating member 36 of the first rail 28, and the first blocking portion 36 a of the operating member 36 is able to be located at a blocking position Y1 (this part can be referred to FIG. 10) in response to a resilient force of the resilient portion 36 b so as to enable the first blocking portion 36 a and the second blocking portion 74 to obstruct each other to prevent the second rail 30 from being moved relative to the first rail 28 from the second position P2 in the first direction D1.

Preferably, when the second rail 30 and the third rail 34 are located at the second position P2 relative to the first rail 28, the first severing feature 50 of the first rail 28 is configured to sever a synchronous relationship between the second rail 30 and the third rail 34. For example, the synchronizing member 38 deflects by an angle through contacting the incline 50 a or the cambered surface of the first severing feature 50 to make the synchronizing feature 80 and the synchronizing member 38 no longer obstruct each other. In other words, the synchronizing member 38 is no longer in the initial state X1 (e.g. in another state X2) so as to sever the synchronous relationship between the second rail 30 and the third rail 34. Therefore, the third rail 34 can be further moved relative to the second rail 30 from the second position P2 in the first direction D1 and detached from the second rail 30 (this part can be referred to FIG. 10 where the third rail 34 has been detached from the passage 62 of the second rail 30). Wherein, the technique related to how to detach the third rail 34 from the second rail 30 is well known by those skilled in the art of the present invention. It is omitted hereby for simplicity.

It is notable when the second rail 30 is located at the second position P2 relative to the first rail 28, a clearance G is between the front ends F of the first bead strip 54 a and the second bead strip 54 b and the front blocking portion 56 of the first rail 28.

As shown in FIGS. 10-13, the second rail 30 can be moved relative to the first rail 28 from the second position P2 to a third position P3 (e.g. a second extending position). Preferably, the operating member 36 is operable to drive the first blocking portion 36 a to leave the blocking position Y1 (e.g. to be located at a non-blocking position Y2, this part can be referred to FIG. 11 and FIG. 12) and no longer to obstruct the second blocking portion 74 of the second rail 30 such that the second rail 30 can be moved relative to the first rail 28 to a third position P3 in the first direction D1.

When the second rail 30 is moved relative to the first rail 28 from the second position P2 to the third position P3 by a distance substantially equal to the clearance G in the first direction D1, the positioning member 64 is moved from the engaging position S2 to a disengaging position S3 by guidance of the incline 42 a or the cambered surface of the second structure 42 of the first rail 28 and no longer abuts against the first structure 40 of the first rail 28 (as shown in FIG. 12 or FIG. 13). During the process, the rear blocking portion 72 of the second rail 30 is able to drive the first bead strip 54 a and the second bead strip 54 b in the first direction D1 until the second rail 30 is located at the third position P3, and the front ends F of the first bead strip 54 a and the second bead strip 54 b have abutted against the front blocking portion 56 of the first rail 28 to prevent the second rail 30 from being further moved relative to the first rail 28 from the third position P3 in the first direction D1. It is notable that during the process where the positioning member 64 is moved from the engaging position S2 (as shown in FIG. 9) to the disengaging position S3 (as shown in FIG. 13), the extending section 64 a of the positioning member 64 will cross a side of the flexible portion 70 a of the holding member 70 and reach another side of the flexible portion 70 a. Through a holding force of the flexible portion 70 a of the holding member 70 exerted to the extending section 64 a of the positioning member 64, the positioning member 64 is held in the disengaging position S3. Preferably, the holding force of the holding member 70 is greater than the elastic force of the first elastic section 66 a of the elastic member 66.

Moreover, the second rail 30 is retractable relative to the first rail 28 from the third position P3 to the first position P1 in the second direction D2. Wherein, since the positioning member 64 is located at the disengaging position S3, the positioning member 64 does not engage with the first structure 40 of the first rail 28 when the second rail 30 is moved in the second direction D2.

It is notable if the second rail 30 is moved relative to the first rail 28 from the second position P2 to the third position P3 in the first direction D1, and the speed of the second rail 30 traveling from the third position P3 in the second direction D2 is fast enough such that the positioning member 64 is too late to respond the elastic force of the first elastic section 66 a of the elastic member 66 and leaves the disengaging position S3, the second rail 30 can be also moved from the third position P3 in the second direction D2. In other words, it is not necessary to hold the positioning member 64 at the disengaging position S3 through the holding member 70 during implementation.

As shown in FIGS. 14-17, when the second rail 30 is moved relative to the first rail 28 to the first position P1 in the second direction D2 (this part can be referred to FIG. 6), the positioning member 64 is released from the holding force of the holding member 70 and moved from the disengaging position S3 back to the initial position S1 by guidance of the incline 52 a or the cambered surface of the second severing feature 52 of the first rail 28 (this part can be referred to FIG. 6). It is notable that during the process where the positioning member 64 is moved from the disengaging position S3 (as shown in FIG. 15) to the initial position S1 (as shown in FIG. 17), the extending section 64 a of the positioning member 64 is moved from the said another side of the flexible portion 70 a of the holding member 70 back to the side of the flexible portion 70 a. On the other hand, the synchronizing member 38 can recover to be in the initial state X1 in response to the elastic force generated by the second elastic section 66 b of the elastic member 66.

Therefore, the slide rail assembly of the present invention is characterized in that:

1. Users do not need to stretch their hands to the rear of the second rail and are able to sever a synchronous relationship between the second rail 30 and the first rail 28 through operating a direction of the displacement with standing in front of the slide rail assembly. It facilitates the retraction of the second rail 30 relative to the first rail 28 and makes the operation faster and more convenient.

2. When the second rail 30 is moved relative to the first rail 28 from the first position P1 to the second position P2 in the first direction D1, the positioning member 64 is moved from the initial position S1 to the engaging position S2 and is able to abut against the first structure 40 of the first rail 28 through the elastic force released by the elastic member 66 to prevent the second rail 30 from being moved relative to the first rail 28 in the second direction D2. When the second rail 30 is moved relative to the first rail 28 from the second position P2 to the third position P3 in the first direction D1, the positioning member 64 is moved from the engaging position S2 to the disengaging position S3 and no longer abuts against the first structure 40 of the first rail 28 by the guidance of the second structure 42 of the first rail 28 to allow the second rail 30 to be moved relative to the first rail 28 in the second direction D2.

3. When the second rail 30 is located at the second position P2 relative to the first rail 28, the first blocking portion 36 a of the operating member 36 is located at the blocking position Y1 and able to obstruct the second blocking portion 74 of the second rail 30 to prevent the second rail 30 from being moved relative to the first rail 28 in the first direction D1.

4. The operating member 36 is operable to drive the first blocking portion 36 a to leave the blocking position Y1 and no longer to obstruct the second blocking portion 74 of the second rail 30 such that the second rail 30 is movable relative to the first rail 28 from the second position P2 to the third position P3 in the first direction D1. The positioning member 64 is moved from the engaging position S2 to the disengaging position S3 by the guidance of the second structure 42 of the first rail 28 and no longer abuts against the first structure 40 of the first rail 28.

5. When the second rail 30 is located at the second position P2 relative to the first rail 28, the clearance G is between the front ends F of the first bead strip 54 a and the second bead strip 54 b and the front blocking portion 56 of the first rail 28, and the second rail 30 is movable relative to the first rail 28 from the second position P2 to the third position P3 by a distance equal to the clearance G in the first direction D1.

6. When the second rail 30 is located at the third position P3 relative to the first rail 28, the rear blocking portion 72 of the second rail 30 is able to abut against the front blocking portion 56 of the first rail 28 through the front ends F of the first bead strip 54 a and the second bead strip 54 b to prevent the second rail 30 from being moved relative to the first rail 28 from the third position P3 in the first direction D1.

7. Compared to the prior art, the present invention is different in the following manners: in US patent application number 2011/0135224, it can be seen from FIGS. 8, 9, 11, 12, 13 in sequence that as the third slide member 22 is moved relative to the second slide member 14 in a first direction (that is, an extension direction to the right of the figures), the positioning device 24 is moved from an initial position to a position shown in FIGS. 11 and 12. As the third slide member 22 is removed from the second slide member 14 (shown in FIG. 13), the positioning device 24 is engaged with the lock portion 40. To disengage the positioning device 24 from the lock portion 40 (and therefore the engagement between the first slide member 12 and the second slide member 14), the third slide member 22 is required to move in a second direction opposite to the first direction relative to the second slide member 14, such that the protrusion 76 of the third slide member 22 abuts an end of the positioning member 80 for the positioning member 80 to be rotated and disengaged from the lock portion 40.

In US patent application number 2011/0280506, it can be seen from FIGS. 6, 7, 8, in sequence that as the second rail 20 is moved in an extension direction relative to the first rail 10, the engaging portion 74 of the engaging member 68 is engaged with the stop end 18 of the positioning portion 16. At this stage, the first rail 10 and the second rail 20 are engaged with each other, and the third rail 30 can be pulled out or extended completely. To disengage the engaging member 68 from the stop end 18 of the positioning portion 16 (and therefore the engagement of the first rail 10 and the second rail 20), the third rail 30 is required to be moved in a retraction direction (opposite to the extension direction) relative to the second rail 20, such that a side wall 34 presses the extension wing 76 of the engaging member 68 for the engaging portion 74 of the engaging member 68 to be released from the stop end 18 of the positioning portion 16.

The slide rail assembly of the present invention differs from the prior art in that the present invention allows the user to establish a synchronous relationship between the second rail 30 and the first rail 28 by moving the second rail 30 relative to the first rail 28 in the first direction D1, all while standing in front of the slide rail assembly. The second rail 30 and the first rail 28 can then be disengaged from each other by continuing to move the second rail 30 relative to the first rail 28 in the same first direction D1. In other words, the first rail 28 and the second rail 30 are engaged with each other via their positional relationship. Additionally, the third rail 34 is not involved in the process to disengage the first rail 28 and the second rail 30 from each other. In this manner, the user can smoothly engage or disengage the synchronous relationship between the second rail 30 and the first rail 28 depending on practical demands, without having to change the direction of movement of the rails like the prior art.

Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims. 

What is claimed is:
 1. A slide rail assembly, comprising: a first rail comprising a first structure and a second structure; a second rail movable relative to the first rail; and a positioning device arranged to the second rail, the positioning device comprising an elastic member and a positioning member, the positioning member being located at an initial position in response to an elastic force generated by the elastic member; wherein when the second rail is moved relative to the first rail from a first position to a second position in a first direction, the positioning member is moved from the initial position to an engaging position through the elastic force released by the elastic member and abuts against the first structure of the first rail; wherein when the second rail is moved relative to the first rail from the second position to a third position in the first direction, the positioning member is moved from the engaging position to a disengaging position by guidance of the second structure of the first rail and no longer abuts against the first structure of the first rail.
 2. The slide rail assembly of claim 1, further comprising a third rail movable relative to the second rail and a synchronizing member pivoted to the second rail, the third rail having a synchronizing feature, the second rail and the third rail being capable of being moved synchronously by means of abutting between the synchronizing feature and the synchronizing member.
 3. The slide rail assembly of claim 2, wherein the first rail further comprising a first severing feature, when the second rail is located at the second position relative to the first rail, the first severing feature of the first rail is configured to sever a synchronous relationship between the second rail and the third rail.
 4. The slide rail assembly of claim 3, wherein the first severing feature comprises an incline or a cambered surface, and the synchronizing member is deflectable through contacting the first severing feature to serve the synchronous relationship between the second rail and the third rail.
 5. The slide rail assembly of claim 1, wherein the first structure is a hole or a concaved portion, the second structure is adjacent to the first structure, and the second structure comprises an incline or a cambered surface.
 6. The slide rail assembly of claim 1, wherein the first position is a retracted position, the second position is a first extending position, and the third position is a second extending position.
 7. The slide rail assembly of claim 1, further comprising a holding member arranged to the second rail, the positioning member being pivoted to the second rail, when the positioning member is located at the disengaging position, the positioning member can be held at the disengaging position by the holding member.
 8. The slide rail assembly of claim 7, wherein the holding member has a flexible portion, the flexible portion is able to exert a holding force to the positioning member.
 9. The slide rail assembly of claim 8, wherein the first rail further comprises a second severing feature, when the second rail is moved relative to the first rail to the first position in a second direction, the positioning member is released from the holding force and moved from the disengaging position back to the initial position by guidance of the second severing feature of the first rail.
 10. The slide rail assembly of claim 9, wherein the second severing feature of the first rail comprises an incline or a cambered surface.
 11. The slide rail assembly of claim 1, further comprising an operating member arranged to the first rail, the operating member comprising a first blocking portion, the second rail having a second blocking portion, when the second rail is moved relative to the first rail to the second position, the first blocking portion and the second blocking portion obstruct each other to prevent the second rail from being moved in the first direction.
 12. The slide rail assembly of claim 11, wherein the operating member is operable to drive the first blocking portion to leave the blocking position and no longer obstruct the second blocking portion of the second rail such that the second rail is movable relative to the first rail to the third position in the first direction.
 13. The slide rail assembly of claim 12, further comprising an auxiliary sliding device arranged between the first rail and the second rail, the auxiliary sliding device comprising a pair of bead strips, each bead strip comprising a plurality of balls configured to support the first rail and the second rail.
 14. The slide rail assembly of claim 13, wherein the second rail has a rear blocking portion corresponding to a rear end of the each bead strip, the first rail has a front blocking portion corresponding to a front end of the each bead strip, the each bead strip is located between the front blocking portion of the first rail and the rear blocking portion of the second rail, when the second rail is located at the second position relative to the first rail, a clearance is between the front end of the each bead strip and the front blocking portion of the first rail. 